Methods for manufacturing bulked continuous filament from colored recycled PET

ABSTRACT

A method of manufacturing bulked continuous carpet filament which, in various embodiments, comprises: (A) grinding recycled PET bottles into a group of flakes; (B) washing the flakes; (C) identifying and removing impurities, including impure flakes, from the group of flakes; (D) adding one or more color concentrates to the flakes; (E) passing the group of flakes through an extrusion system while maintaining the pressure within the extrusion system below about 25 millibars; (F) passing the resulting polymer melt through at least one filter having a micron rating of less than about 50 microns; and (G) forming the recycled polymer into bulked continuous carpet filament that consists essentially of recycled PET.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/419,955, filed Jan. 30, 2017, now U.S. Pat. No. 10,487,422, issuedNov. 26, 2019, entitled “Methods for Manufacturing Bulked ContinuousFilament from Colored Recycled PET,” which is a continuation-in-part ofU.S. patent application Ser. No. 15/396,143, filed Dec. 30, 2016, nowU.S. Pat. No. 10,493,660, issued Dec. 3, 2019, entitled “Systems andMethods for Manufacturing Bulked Continuous Filament,” which is acontinuation of U.S. patent application Ser. No. 13/892,713, filed May13, 2013 and issued as U.S. Pat. No. 9,550,338, entitled “Systems andMethods for Manufacturing Bulked Continuous Filament,” which is adivisional of U.S. patent application Ser. No. 13/721,955, filed Dec.20, 2012 and issued as U.S. Pat. No. 8,597,553, entitled “Systems andMethods for Manufacturing Bulked Continuous Filament,” which claimspriority to U.S. Provisional Patent Application No. 61/654,016, filedMay 31, 2012, entitled “Systems and Methods for Manufacturing BulkedContinuous Fiber,” each of which is hereby incorporated herein byreference in its entirety.

BACKGROUND

Because pure virgin PET polymer is more expensive than recycled PETpolymer, and because of the environmental benefits associated with usingrecycled polymer, it would be desirable to be able to produce bulkedcontinuous carpet filament, and other items, from 100% recycled PETpolymer (e.g., PET polymer from post-consumer PET bottles).

SUMMARY

Various embodiments are directed to a method of manufacturing bulkedcontinuous carpet filament from recycled PET that includes both clearand colored PET. In particular embodiments, the method includes: (A)providing an extrusion system that comprises a first extruder, a secondextruder, and a pressure regulation system that is adapted to maintain apressure within the first and second extruders between about 0 millibarsand about 5 millibars; (B) using the pressure regulation system toreduce a pressure within the first and second extruders to between about0 millibars and about 5 millibars; (C) providing a plurality of polymerflakes, the plurality of polymer flakes comprising between about sixpercent and about ten percent colored recycled polyethyleneterephthalate (PET) flakes and balance substantially clear recycled PETflakes; (D) providing one or more color additives; (E) adding the one ormore color additives to the plurality of polymer flakes such that theresulting mixture comprises between about zero percent and about threepercent of the one or more color additives by weight; (F) whilemaintaining the pressure within the first and second extruders betweenabout 0 millibars and about 5 millibars, passing the plurality ofpolymer flakes and the one or more color additives through the extrusionsystem to form a polymer melt so that a first portion of the polymermelt passes through the first extruder and a second portion of thepolymer melt passes through the second extruder; and (G) after the stepof passing the polymer melt through the extrusion system, forming therecycled polymer into bulked continuous carpet filament.

A method of manufacturing carpet filament from clear and coloredrecycled PET bottles, according to particular embodiments, includes thesteps of: (A) providing a plurality of recycled PET bottles; (B)grinding the plurality of recycled PET bottles into a group of polymerflakes, the group of polymer flakes comprising up to about ten percentcolored polymer flakes and balance substantially clear polymer flakes;(C) washing the group of polymer flakes; (D) providing a color additive;(E) mixing the color additive with the group of polymer flakes to form acolor additive-polymer mixture comprising up to about three percentcolor additive by weight; (F) melting the color additive-polymer mixtureto produce a polymer melt; (G) providing an extruder that extrudesmaterial in a plurality of different extrusion streams; (H) reducing apressure within the extruder to between about 0 millibars and about 12millibars; (I) while maintaining the pressure within the extruderbetween about 0 millibars and about 12 millibars, passing the polymermelt through the extruder so that the polymer melt is divided into aplurality of extrusion streams, each having a pressure between about 0millibars and about 12 millibars; (J) after passing the polymer meltthrough the extruder, filtering the polymer melt through at least onefilter; and (K) after passing the polymer melt through the filter,forming the polymer melt into bulked continuous carpet filament.

A method of manufacturing bulked continuous carpet filament, in someembodiments, includes: (A) providing an extrusion system that comprisesa first extruder, a second extruder, a third extruder, a fourthextruder, and a pressure regulation system that is adapted to maintain apressure within the first, second, third, and fourth extruders betweenabout 1 millibar and about 18 millibars; (B) using the pressureregulation system to reduce a pressure within the first, second, third,and fourth extruders to between about 0 millibars and about 18millibars; (C) while maintaining the pressure within the first, second,third, and fourth extruders between about 1 millibar and about 18millibars, passing a polymer melt through the extrusion system so that:(1) a first portion of the melt passes through the first extruder, (2) asecond portion of the melt passes through the second extruder, (3) athird portion of the melt passes through the third extruder, and (4) afourth portion of the melt passes through the fourth extruder, whereinthe polymer melt comprises between about seven percent and about ninepercent colored recycled PET by weight, between about two percent andabout three percent color additive by weight, and balance recycledsubstantially clear PET; and (D) after the step of passing the polymermelt through the extrusion system, forming the polymer melt into bulkedcontinuous carpet filament.

BRIEF DESCRIPTION OF THE DRAWINGS

Having described various embodiments in general terms, reference willnow be made to the accompanying drawings, which are not necessarilydrawn to scale, and wherein:

FIG. 1 depicts a process flow, according to a particular embodiment, formanufacturing bulked continuous carpet filament.

FIG. 2 is a perspective view of an exemplary MRS extruder that issuitable for use in the process of FIG. 1.

FIG. 3 is a cross-sectional view of an exemplary MRS section of the MRSextruder of FIG. 2.

FIG. 4 depicts a process flow depicting the flow of polymer through anMRS extruder and filtration system according to a particular embodiment.

FIG. 5 is a high-level flow chart of a method, according to variousembodiments, of manufacturing bulked continuous carpet filament.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Various embodiments will now be described in greater detail. It shouldbe understood that the invention may be embodied in many different formsand should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like numbers refer to likeelements throughout.

I. Overview

New processes for making fiber from recycled polymer (e.g., recycled PETpolymer) are described below. In various embodiments, this new process:(1) is more effective than earlier processes in removing contaminatesand water from the recycled polymer; and/or (2) does not require thepolymer to be melted and cooled as many times as in earlier processes.In at least one embodiment, the improved process results in a recycledPET polymer having a polymer quality that is high enough that the PETpolymer may be used in producing bulked continuous carpet filament from100% recycled PET content (e.g., 100% from PET obtained from previouslyused PET bottles). In particular embodiments, the recycled PET polymerhas an intrinsic viscosity of at least about 0.79 dL/g (e.g., of betweenabout 0.79 dL/g and about 1.00 dL/g).

II. More Detailed Discussion

A BCF (bulked continuous filament) manufacturing process, according to aparticular embodiment, may comprise three steps: (1) preparing flakes ofPET polymer from post-consumer bottles for use in the process; (2)passing the flakes through an extruder that melts the flakes andpurifies the resulting PET polymer; and (3) feeding the purified polymerinto a spinning machine that turns the polymer into filament for use inmanufacturing carpets. These three steps are described in greater detailbelow.

Step 1: Preparing Flakes of Pet Polymer from Post-Consumer Bottles

In a particular embodiment, the step of preparing flakes of PET polymerfrom post-consumer bottles comprises: (A) sorting post-consumer PETbottles and grinding the bottles into flakes; (B) washing the flakes;and (C) identifying and removing any impurities or impure flakes.

A. Sorting Post-Consumer PET Bottles and Grinding the Bottles intoFlakes

In particular embodiments, bales of clear and mixed colored recycledpost-consumer (e.g., “curbside”) PET bottles (or other containers)obtained from various recycling facilities make-up the post-consumer PETcontainers for use in the process. In other embodiments, the source ofthe post-consumer PET containers may be returned ‘deposit’ bottles(e.g., PET bottles whose price includes a deposit that is returned to acustomer when the customer returns the bottle after consuming thebottle's contents). The curbside or returned “post-consumer” or“recycled” containers may contain a small level of non-PET contaminates.The contaminants in the containers may include, for example, non-PETpolymeric contaminants (e.g., PVC, PLA, PP, PE, PS, PA, etc.), metal(e.g., ferrous and non-ferrous metal), paper, cardboard, sand, glass orother unwanted materials that may find their way into the collection ofrecycled PET. The non-PET contaminants may be removed from the desiredPET components, for example, through one or more of the variousprocesses described below.

In particular embodiments, smaller components and debris (e.g.,components and debris greater than 2 inches in size) are removed fromthe whole bottles via a rotating trammel. Various metal removal magnetsand eddy current systems may be incorporated into the process to removeany metal contaminants. Near Infra-Red optical sorting equipment such asthe NRT Multi Sort IR machine from Bulk Handling Systems Company ofEugene, Oreg., or the Spyder IR machine from National RecoveryTechnologies of Nashville, Tenn., may be utilized to remove any loosepolymeric contaminants that may be mixed in with the PET flakes (e.g.,PVC, PLA, PP, PE, PS, and PA). Additionally, automated X-ray sortingequipment such as a VINYLCYCLE machine from National RecoveryTechnologies of Nashville, Tenn. may be utilized to remove remaining PVCcontaminants.

In particular embodiments, a binary segregation of the clear materialsfrom the colored materials is achieved using automated color sortingequipment equipped with a camera detection system (e.g., a Multisort ESmachine from National Recovery Technologies of Nashville, Tenn.). Invarious embodiments, manual sorters are stationed at various points onthe line to remove contaminants not removed by the sorter and anycolored bottles. In particular embodiments, the sorted material is takenthrough a granulation step (e.g., using a 50B Granulator machine fromCumberland Engineering Corporation of New Berlin, Wis.) to size reduce(e.g., grind) the bottles down to a size of less than one half of aninch. In various embodiments, the bottle labels are removed from theresultant “dirty flake” (e.g., the PET flakes formed during thegranulation step) via an air separation system prior to entering thewash process.

B. Washing the Flakes

In particular embodiments, the “dirty flake” is then mixed into a seriesof wash tanks. As part of the wash process, in various embodiments, anaqueous density separation is utilized to separate any olefin bottlecaps (which may, for example, be present in the “dirty flake” asremnants from recycled PET bottles) from the higher specific gravity PETflakes. In particular embodiments, the flakes are washed in a heatedcaustic bath to about 190 degrees Fahrenheit. In particular embodiments,the caustic bath is maintained at a concentration of between about 0.6%and about 1.2% sodium hydroxide. In various embodiments, soapsurfactants as well as defoaming agents are added to the caustic bath,for example, to further increase the separation and cleaning of theflakes. A double rinse system then washes the caustic from the flakes.

In various embodiments, the flake is centrifugally dewatered and thendried with hot air to at least substantially remove any surfacemoisture. The resultant “clean flake” is then processed through anelectrostatic separation system (e.g., an electrostatic separator fromCarpco, Inc. of Jacksonville, Fla.) and a flake metal detection system(e.g., an MSS Metal Sorting System) to further remove any metalcontaminants that remain in the flake. In particular embodiments, an airseparation step removes any remaining label from the clean flake. Invarious embodiments, the flake is then taken through a flake colorsorting step (e.g., using an OPTIMIX machine from TSM Control Systems ofDundalk, Ireland) to remove any remaining color contaminants remainingin the flake. In various embodiments, an electro-optical flake sorterbased at least in part on Raman technology (e.g., a Powersort 200 fromUnisensor Sensorsysteme GmbH of Karlsruhe, Germany) performs the finalpolymer separation to remove any non-PET polymers remaining in theflake. This step may also further remove any remaining metalcontaminants and color contaminants.

In various embodiments, the combination of these steps deliverssubstantially clean (e.g., clean) PET bottle flake comprising less thanabout 50 parts per million PVC (e.g., 25 ppm PVC) and less than about 15parts per million metals for use in the downstream extrusion processdescribed below.

C. Identifying and Removing Impurities and Impure Flakes

In particular embodiments, after the flakes are washed, they are feddown a conveyor and scanned with a high-speed laser system 300. Invarious embodiments, particular lasers that make up the high-speed lasersystem 300 are configured to detect the presence of particularcontaminates (e.g., PVC or Aluminum). Flakes that are identified as notconsisting essentially of PET may be blown from the main stream offlakes with air jets. In various embodiments, the resulting level ofnon-PET flakes is less than 25 ppm.

In various embodiments, the system is adapted to ensure that the PETpolymer being processed into filament is substantially free of water(e.g., entirely free of water). In a particular embodiment, the flakesare placed into a pre-conditioner for between about 20 and about 40minutes (e.g., about 30 minutes) during which the pre-conditioner blowsthe surface water off of the flakes. In particular embodiments,interstitial water remains within the flakes. In various embodiments,these “wet” flakes (e.g., flakes comprising interstitial water) may thenbe fed into an extruder (e.g., as described in Step 2 below), whichincludes a vacuum setup designed to remove—among other things—theinterstitial water that remains present in the flakes following thequick-drying process described above.

Step 2: Using an Extrusion System to Melt and Purify PET Flakes

In particular embodiments, an extruder is used to turn the wet flakesdescribed above into a molten recycled PET polymer and to perform anumber of purification processes to prepare the polymer to be turnedinto BCF for carpet. As noted above, in various embodiments, after STEP1 is complete, the recycled PET polymer flakes are wet (e.g., surfacewater is substantially removed (e.g., fully removed) from the flakes,but interstitial water remains in the flakes). In particularembodiments, these wet flakes are fed into a Multiple Rotating Screw(“MRS”) extruder 400. In other embodiments, the wet flakes are fed intoany other suitable extruder (e.g., a twin screw extruder, a multiplescrew extruder, a planetary extruder, or any other suitable extrusionsystem). An exemplary MRS Extruder 400 is shown in FIGS. 2 and 3. Aparticular example of such an MRS extruder is described in U.S.Published Patent Application 2005/0047267, entitled “Extruder forProducing Molten Plastic Materials”, which was published on Mar. 3,2005, and which is hereby incorporated herein by reference.

As may be understood from this figure, in particular embodiments, theMRS extruder includes a first single-screw extruder section 410 forfeeding material into an MRS section 420 and a second single-screwextruder section 440 for transporting material away from the MRSsection.

In various embodiments, the wet flakes are fed directly into the MRSextruder 400 substantially immediately (e.g., immediately) following thewashing step described above (e.g., without drying the flakes orallowing the flakes to dry). In particular embodiments, a system thatfeeds the wet flakes directly into the MRS Extruder 400 substantiallyimmediately (e.g., immediately) following the washing step describedabove may consume about 20% less energy than a system that substantiallyfully pre-dries the flakes before extrusion (e.g., a system thatpre-dries the flakes by passing hot air over the wet flakes for aprolonged period of time). In various embodiments, a system that feedsthe wet flakes directly into the MRS Extruder 400 substantiallyimmediately (e.g., immediately) following the washing step describedabove avoids the need to wait a period of time (e.g., up to eight hours)generally required to fully dry the flakes (e.g., remove all of thesurface and interstitial water from the flakes).

FIG. 4 depicts a process flow that illustrates the various processesperformed by the MRS Extruder 400 in a particular embodiment. In theembodiment shown in this figure, the wet flakes are first fed throughthe MRS extruder's first single-screw extruder section 410, which may,for example, generate sufficient heat (e.g., via shearing) to at leastsubstantially melt (e.g., melt) the wet flakes.

In the embodiment shown in this figure, the system is further configuredto add a Solution Dye Color Concentrate 415 to the flakes (e.g., wetflakes) before feeding the flakes into the first singe-screw extrudersection 410. In particular embodiments, the Solution Dye ColorConcentrate 415 may include any suitable color concentrate, which may,for example, result in a particular color of polymer fiber followingextrusion. In particular embodiments, the color concentrate may comprisepelletized color concentrate as well as a carrier resin which may, forexample, bind the colorant to the polymer. In various embodiments,adding color concentrate to the flakes prior to extrusion may result inpolymer filament that is at least partially impregnated (e.g.,impregnated) with a color pigment. In particular embodiments, carpetproduced from solution dyed filament may be highly resistant to colorloss through fading from sunlight, ozone, harsh cleaning agents such asbleach, or other factors.

In various embodiments, the system is configured to adjust an amount ofSolution Dye Color Concentrate 415 to add to the flakes prior to feedingthe flakes thought the first single-screw extruder section 410. Inparticular embodiments, the system is configured to add between abouttwo percent and about three percent color concentrate by mass to thepolymer flake. In other embodiments, the system is configured to betweenabout zero percent and about three percent color concentrate by mass. Instill other embodiments, the system is configured to add up to about sixpercent color concentrate by mass to the polymer flake prior toextrusion. In some embodiments, the system is configured to add betweenabout one percent and three percent color concentrate by mass to thepolymer flake. In still other embodiments, the system is configured toadd any suitable ratio of color concentrate to polymer flake in order toachieve a particular color of molten polymer (and ultimately polymerfiber) following extrusion.

Although in the embodiment shown in this figure, the Solution Dye ColorConcentrate 415 is depicted as added to the polymer flake prior tofeeding the flake through the first single-screw extruder section 410,it should be understood that in other embodiments, the Solution DyeColor Concentrate 15 may be added during any other suitable phase of theprocess described in this document. For example, In various embodiments,the system is configured to add the Solution Dye Color Concentrate 415following extrusion of the polymer flake by the first single-screwextruder section 410 but prior to feeding the resultant polymer meltthrough the extruder's MRS section 420 discussed below. In still otherembodiments, the system may add the Solution Dye Color Concentrate 415after the flake has passed through the MRS extruder's MRS section 420prior to passing the polymer melt through the second single screwsection 440 discussed below. In still other embodiments, they system mayadd the Solution dye Color Concentrate 415 while the flakes and/orpolymer melt are being extruded in the first single-screw extrudersection 410, MRS Section 420, second single screw section 440, or at anyother suitable phase of the process. In still other embodiments, thesystem may add the Solution Dye Color Concentrate 415 during one or more(e.g., a plurality) of the phases of the process described herein (e.g.,the system may add some Solution Dye Color Concentrate 415 to thepolymer flake prior to passing the flake through the single-screwextruder section 410 and some additional solution Dye Color Concentrate415 following extrusion through the MRS Section 420).

Following the addition of the color concentrate and extrusion by thefirst single-screw extruder section 410, the resultant polymer melt(e.g., comprising the melted flakes and color concentrate), in variousembodiments, is then fed into the extruder's MRS section 420, in whichthe extruder separates the melt flow into a plurality of differentstreams (e.g., 4, 6, 8, or more streams) through a plurality of openchambers. FIG. 3 shows a detailed cutaway view of an MRS Section 420according to a particular embodiment. In particular embodiments, such asthe embodiment shown in this figure, the MRS Section 420 separates themelt flow into eight different streams, which are subsequently fedthrough eight satellite screws 425A-H. As may be understood from FIG. 2,in particular embodiments, these satellite screws are substantiallyparallel (e.g., parallel) to one other and to a primary screw axis ofthe MRS Machine 400.

In the MRS section 420, in various embodiments, the satellite screws425A-H may, for example, rotate faster than (e.g., about four timesfaster than) in previous systems. As shown in FIG. 3, in particularembodiments: (1) the satellite screws 425A-H are arranged within asingle screw drum 428 that is mounted to rotate about its central axis;and (2) the satellite screws 425A-H are configured to rotate in adirection that is opposite to the direction in which the single screwdrum rotates 428. In various other embodiments, the satellite screws425A-H and the single screw drum 428 rotate in the same direction. Inparticular embodiments, the rotation of the satellite screws 425A-H isdriven by a ring gear. Also, in various embodiments, the single screwdrum 428 rotates about four times faster than each individual satellitescrew 425A-H. In certain embodiments, the satellite screws 425A-H rotateat substantially similar (e.g., the same) speeds.

In various embodiments, as may be understood from FIG. 4, the satellitescrews 425A-H are housed within respective extruder barrels, which may,for example be about 30% open to the outer chamber of the MRS section420. In particular embodiments, the rotation of the satellite screws425A-H and single screw drum 428 increases the surface exchange of thepolymer melt (e.g., exposes more surface area of the melted polymer tothe open chamber than in previous systems). In various embodiments, theMRS section 420 creates a melt surface area that is, for example,between about twenty and about thirty times greater than the meltsurface area created by a co-rotating twin screw extruder. In aparticular embodiment, the MRS section 420 creates a melt surface areathat is, for example, about twenty five times greater than the meltsurface area created by a co-rotating twin screw extruder.

In various embodiments, the MRS extruder's MRS Section 420 is fittedwith a Vacuum Pump 430 that is attached to a vacuum attachment portion422 of the MRS section 420 so that the Vacuum Pump 430 is incommunication with the interior of the MRS section via a suitableopening 424 in the MRS section's housing. In still other embodiments,the MRS Section 420 is fitted with a series of Vacuum Pumps. Inparticular embodiments, the Vacuum Pump 430 is configured to reduce thepressure within the interior of the MRS Section 420 to a pressure thatis between about 0.5 millibars and about 5 millibars. In particularembodiments, the Vacuum Pump 430 is configured to reduce the pressure inthe MRS Section 420 to less than about 1.5 millibars (e.g., about 1millibar or less). The low-pressure vacuum created by the Vacuum Pump430 in the MRS Section 420 may remove, for example: (1) volatileorganics present in the melted polymer as the melted polymer passesthrough the MRS Section 420; and/or (2) at least a portion of anyinterstitial water that was present in the wet flakes when the wetflakes entered the MRS Extruder 400. In various embodiments, thelow-pressure vacuum removes substantially all (e.g., all) of the waterand contaminants from the polymer stream.

In a particular example, the Vacuum Pump 430 comprises three mechanicallobe vacuum pumps (e.g., arranged in series) to reduce the pressure inthe chamber to a suitable level (e.g., to a pressure of about 1.0millibar). In other embodiments, rather than the three mechanical lobevacuum pump arrangement discussed above, the Vacuum Pump 430 includes ajet vacuum pump fit to the MRS extruder. In various embodiments, the jetvacuum pump is configured to achieve about 1 millibar of pressure in theinterior of the MRS section 420 and about the same results describedabove regarding a resulting intrinsic viscosity of the polymer melt. Invarious embodiments, using a jet vacuum pump can be advantageous becausejet vacuum pumps are steam powered and therefore substantiallyself-cleaning (e.g., self-cleaning), thereby reducing the maintenancerequired in comparison to mechanical lobe pumps (which may, for example,require repeated cleaning due to volatiles coming off and condensing onthe lobes of the pump). In a particular embodiment, the Vacuum Pump 430is a jet vacuum pump is made by Arpuma GmbH of Bergheim, Germany.

In particular embodiments, after the molten polymer is run through themulti-stream MRS Section 420, the streams of molten polymer arerecombined and flow into the MRS extruder's second single screw section440. In various embodiments, the single stream of molten polymer is nextrun through a filtration system 450 that includes at least one filter.In a particular embodiment, the filtration system 450 includes twolevels of filtration (e.g., a 40 micron screen filter followed by a 25micron screen filter). Although, in various embodiments, water andvolatile organic impurities are removed during the vacuum process asdiscussed above, particulate contaminates such as, for example, aluminumparticles, sand, dirt, and other contaminants may remain in the polymermelt. Thus, this filtration step may be advantageous in removingparticulate contaminates (e.g., particulate contaminates that were notremoved in the MRS Section 420).

In particular embodiments, a viscosity sensor 460 (see FIG. 4) is usedto sense the melt viscosity of the molten polymer stream following itspassage through the filtration system 450. In various embodiments, theviscosity sensor 460, measures the melt viscosity of the stream, forexample, by measuring the stream's pressure drop across a known area. Inparticular embodiments, in response to measuring an intrinsic viscosityof the stream that is below a predetermined level (e.g., below about 0.8g/dL), the system may: (1) discard the portion of the stream with lowintrinsic viscosity; and/or (2) lower the pressure in the MRS Section420 in order to achieve a higher intrinsic viscosity in the polymermelt. In particular embodiments, decreasing the pressure in the MRSSection 420 is executed in a substantially automated manner (e.g.,automatically) using the viscosity sensor in a computer-controlledfeedback control loop with the vacuum section 430.

In particular embodiments, removing the water and contaminates from thepolymer improves the intrinsic viscosity of the recycled PET polymer byallowing polymer chains in the polymer to reconnect and extend the chainlength. In particular embodiments, following its passage through the MRSSection 420 with its attached Vacuum Pump 430, the recycled polymer melthas an intrinsic viscosity of at least about 0.79 dL/g (e.g., of betweenabout 0.79 dL/g and about 1.00 dL/g). In particular embodiments, passagethrough the low pressure MRS Section 420 purifies the recycled polymermelt (e.g., by removing the contaminants and interstitial water) andmakes the recycled polymer substantially structurally similar to (e.g.,structurally the same as) pure virgin PET polymer. In particularembodiments, the water removed by the vacuum includes both water fromthe wash water used to clean the recycled PET bottles as describedabove, as well as from unreacted water generated by the melting of thePET polymer in the single screw heater 410 (e.g., interstitial water).In particular embodiments, the majority of water present in the polymeris wash water, but some percentage may be unreacted water.

Returning to FIG. 4, in particular embodiments, a Color Sensor 470 isused to determine a color of the resultant polymer melt. In variousembodiments, the Color Sensor 470 comprises one or more spectrographsconfigured to separate light shone through the polymer melt into afrequency spectrum to determine the color of the polymer melt. In stillother embodiments, the Color Sensor 470 comprises one or more cameras orother suitable imaging devices configured to determine a color of theresultant polymer melt. In particular embodiments, in response todetermining that the color of the polymer melt is a color other than adesired color (e.g., the polymer melt is lighter than desired, darkerthan desired, a color other than the desired color, etc.) the systemmay: (1) discard the portion of the stream with the incorrect color;and/or (2) adjust an amount of Solution Dye Color Concentrate 415 thatis added to the flake and/or the polymer melt upstream in order toadjust a color of the resultant polymer melt. In particular embodiments,adjusting the amount of Solution Dye Color Concentrate 415 is executedin a substantially automated manner (e.g., automatically) using theColor Sensor 470 in a computer-controlled feedback control loop.

In particular embodiments, the resulting polymer is a recycled PETpolymer (e.g., obtained 100% from post-consumer PET products, such asPET bottles or containers) having a polymer quality that is suitable foruse in producing PET carpet filament using substantially only (e.g.,only) PET from recycled PET products.

Step 3: Purified PET Polymer Fed into Spinning Machine to be Turned intoCarpet Yarn

In particular embodiments, after the recycled PET polymer has beenextruded and purified by the above-described extrusion process, theresulting molten recycled PET polymer is fed directly into a BCF (or“spinning”) machine 500 that is configured to turn the molten polymerinto bulked continuous filament. For example, in various embodiments,the output of the MRS extruder 400 is connected substantially directly(e.g., directly) to the input of the spinning machine 500 so that moltenpolymer from the extruder is fed directly into the spinning machine 500.This process may be advantageous because molten polymer may, in certainembodiments, not need to be cooled into pellets after extrusion (as itwould need to be if the recycled polymer were being mixed with virginPET polymer). In particular embodiments, not cooling the recycled moltenpolymer into pellets serves to avoid potential chain scission in thepolymer that might lower the polymer's intrinsic viscosity.

In particular embodiments, the spinning machine 500 extrudes moltenpolymer through small holes in a spinneret in order to produce carpetyarn filament from the polymer. In particular embodiments, the moltenrecycled PET polymer cools after leaving the spinneret. The carpet yarnis then taken up by rollers and ultimately turned into filaments thatare used to produce carpet. In various embodiments, the carpet yarnproduced by the spinning machine 500 may have a tenacity between about 3gram-force per unit denier (gf/den) and about 9 gf/den. In particularembodiments, the resulting carpet yarn has a tenacity of at least about3 gf/den.

In particular embodiments, the spinning machine 500 used in the processdescribed above is the Sytec One spinning machine manufactured byOerlika Neumag of Neumuenster, Germany. The Sytec One machine may beespecially adapted for hard-to-run fibers, such as nylon orsolution-dyed fibers, where the filaments are prone to breakage duringprocessing. In various embodiments, the Sytec One machine keeps the runsdownstream of the spinneret as straight as possible, uses only onethreadline, and is designed to be quick to rethread when there arefilament breaks.

Although the example described above describes using the Sytec Onespinning machine to produce carpet yarn filament from the polymer, itshould be understood that any other suitable spinning machine may beused. Such spinning machines may include, for example, any suitableone-threadline or three-threadline spinning machine made by OerlikaNeumag of Neumuenster, Germany or any other company.

In various embodiments, the improved strength of the recycled PETpolymer generated using the process above allows it to be run at higherspeeds through the spinning machine 500 than would be possible usingpure virgin PET polymer. This may allow for higher processing speedsthan are possible when using virgin PET polymer.

Summary of Exemplary Process

FIG. 5 provides a high-level summary of various embodiments of themethod of manufacturing bulked continuous filament described above. Asshown in the figure, the method begins at Step 602, where recycled PETbottles are ground into a group of flakes. Next, at Step 604, the groupof flakes is washed to remove contaminants from the flakes' respectiveouter surfaces. Next, at Step 606, the group of flakes is scanned (e.g.,using one or more of the methods discussed above) to identifyimpurities, including impure flakes. These impurities, and impureflakes, are then removed from the group of flakes.

Next, at Step 608, the group of flakes is passed through an MRS extruderwhile maintaining the pressure within an MRS portion of the extruderbelow about 1.5 millibars. At Step 610, the resulting polymer melt ispassed through at least one filter having a micron rating of less thanabout 50 microns. Finally, at Step 612, the recycled polymer is formedinto bulked continuous carpet filament, which may be used in producingcarpet. The method then ends at Step 614.

Alternative Embodiments

In particular embodiments, the system may comprise alternativecomponents or perform alternative processes in order to producesubstantially continuous BCF from 100% recycled PET, or other recycledpolymer. Exemplary alternatives are discussed below.

Non-MRS Extrusion System

In particular embodiments, the process may utilize a polymer flowextrusion system other than the MRS Extruder described above. Thealternative extrusion system may include for example, a twin screwextruder, a multiple screw extruder, a planetary extruder, or any othersuitable extrusion system. In a particular embodiment, the process mayinclude a plurality of any combination of any suitable conical screwextruders (e.g., four twin screw extruders, three multiple screwextruders, etc.).

Making Carpet Yarn from 100% Recycled Carpet

In particular embodiments, the process described above may be adaptedfor processing and preparing old carpet (or any other suitablepost-consumer product) to produce new carpet yarn comprising 100%recycled carpet. In such embodiments, the process begins by grinding andwashing recycled carpet rather than recycled PET bottles. In variousembodiments where old carpet is converted into new carpet yarncomprising 100% recycled carpet, the process may comprise additionalsteps to remove additional materials or impurities that may be presentin recycled carpet that may not be present in recycled PET bottles(e.g., carpet backing, adhesive, etc.).

Other Sources of Recycled PET

In various embodiments, the process described above is adapted forprocessing recycled PET from any suitable source (e.g., sources otherthan recycled bottles or carpet) to produce new carpet yarn comprising100% recycled PET.

The Use of a Crystallizer as Part of BCF Process

In various embodiments, the process for producing recycled BCF mayfurther include a crystallizing step that utilizes one or more PETcrystallizers. In particular embodiments, the system is configured toperform the crystallization step on the ground flakes prior to runningthe flakes through the one or more extruders (e.g., single screwextruder, MRS extruder, etc.). In particular embodiments, the PETcrystallizer comprises a housing, a hopper screw (e.g., an auger)disposed at least partially within the housing, a stirring apparatus,one or more heating elements, and one or more blowers.

Hopper Screw

In particular embodiments, the hopper screw comprises any suitable screwconveyor (e.g., such as an Archimedes' screw) for moving liquid orgranular materials (e.g., such as PET flakes). In various embodiments,the hopper screw comprises a substantially cylindrical shaft and ahelical screw blade disposed along at least a portion of the cylindricalshaft. In particular embodiments, the substantially cylindrical shaft isconfigured to rotate the screw blade, causing that hopper screw to movematerial (e.g., the PET flakes) along the cylindrical shaft and into thecrystallizer housing. In other embodiments, the hopper screw comprisesany other suitable screw conveyer such as, for example, a shaftlessspiral. In embodiments in which the hopper screw comprises a shaftlessspiral, the shaftless spiral may be substantially fixed at one end andfree at the other end and configured to be driven at the fixed end. Invarious embodiments, the hopper screw is disposed at least partiallywithin the crystallizer housing.

In various embodiments, the hopper screw is configured to feed PETflakes into the crystallizer. In various embodiments, the PETcrystallizer is configured to feed the PET flakes into the crystallizerusing the hopper screw relatively slowly.

One or More Heating Elements

In various embodiments, the crystallizer comprises one or more heatingelements for raising a temperature within the crystallizer. Inparticular embodiments, the one or more heating elements comprise one ormore electric heating elements, one or more gas-fired heating elements,or any other suitable heating elements. In some embodiments, the one ormore heating elements may be substantially electrically powered. Invarious embodiments, the one or more heating elements comprise one ormore infra-red heating elements. In other embodiments, the one or moreheating elements may utilize natural gas such, for example, propane. Inparticular embodiments, the one or more heating elements are configuredto raise a temperature within the crystallizer to between about 100degrees Fahrenheit and about 180 degrees Fahrenheit. In still otherembodiments, the one or more heating elements are configured to raise atemperature within the crystallizer to between about 100 degrees Celsiusand 180 degrees Celsius. In some embodiments, the one or more heatingelements are configured to maintain a temperature within thecrystallizer that is substantially about a maximum crystallizationtemperature of PET. In particular embodiments, the maximumcrystallization temperature of PET is between about 140 degrees Celsiusand about 230 degrees Celsius.

One or More Blowers

In various embodiments, the crystallizer further comprises one or moreblowers configured to blow air over the flakes as the flakes passesthrough the crystallizer. In particular embodiments, the one or moreblowers comprise any suitable blowers for moving air substantiallyacross a surface area of the flakes as the flakes pass through thecrystallizer. For example, in some embodiments, the one or more blowerscomprise one or more suitable fans or other suitable mechanisms formoving air. In various embodiments, the one or more blowers areconfigured to blow air that has been at least partially heated by theone or more heating elements. In particular embodiments, the one or moreblowers are configured to blow air having a temperature of at leastabout 140 degree Fahrenheit. In another particular embodiments, the oneor more blowers are configured to blow air having a temperature of atleast about 140 degree Celsius. In other embodiments, the one or moreblowers are configured to maintain the temperature in the crystallizerbetween about 140 degrees Fahrenheit and about 180 degrees Fahrenheit.In some embodiments, the one or more blowers are configured to blow hotair from a bottom portion of the crystallizer and draw air from an upperportion of the crystallizer.

Stirring Apparatus

In various embodiments, the crystallizer comprises a stirring apparatusthat comprises any suitable apparatus for stirring the PET flakes whilethe PET flakes are passing through the crystallizer. In variousembodiments, the stirring apparatus may be operated, for example, by anysuitable gear motor. In a particular embodiment, the stirring apparatuscomprises a suitable rod or other suitable mechanism mounted to rotate,or otherwise stir the PET flakes as the PET flakes are passing throughthe crystallizer. In other embodiments, the stirring apparatus maycomprise any suitable tumbler, which may, for example, comprise a drummounted to rotate via the gear motor such that the PET flakes are atleast partially stirred and/or agitated while the PET flakes are withinthe drum. In still other embodiments, the stirring apparatus comprisesone or more screws and/or augers configured to rotate and stir the PETflakes. In particular embodiments, the stirring apparatus comprises thehopper screw.

As may be understood from this disclosure, the stirring apparatus isconfigured to agitate or stir the PET flakes as the one or more blowersblow air heated by the one or more heating elements across the PETflakes. In particular embodiments, the stirring apparatus is configuredto at least partially reduce agglomeration (e.g., sticking or clumpingof the flake) while the flake is at least partially crystallizing in thecrystallizer.

In particular embodiments, the crystallizer at least partially dries thesurface of the PET flakes. In various embodiments, the PET crystallizeris configured to reduce a moisture content of the PET flakes to about 50ppm. In other embodiments the PET crystallizer is configured to reduce amoisture content of the PET flakes to between about 30 and about 50 ppm.

In various embodiments, the use of drier flakes may enable the system torun the flakes through the MRS extruder more slowly, which may allow forhigher pressure within the MRS extruder during extrusion (e.g., mayenable the system to maintain a higher pressure within the MRS extruder,rather than very low pressure). In various embodiments of the process,the pressure regulation system may be configured to maintain a pressurewithin the MRS extruder of between about 0 millibars and about 25millibars. In particular embodiments, such as embodiments in which thePET flakes have been run through a crystallizer before being extruded inthe MRS extruder, the pressure regulation system may be configured tomaintain a pressure within the MRS extruder of between about 0 and about18 millibars. In other embodiments, the pressure regulation system maybe configured to maintain a pressure within the MRS extruder betweenabout 0 and about 12 millibars. In still other embodiments, the pressureregulation system may be configured to maintain a pressure within theMRS extruder between about 0 and about 8 millibars. In still otherembodiments, the pressure regulation system may be configured tomaintain a pressure within the MRS extruder between about 5 millibarsand about 10 millibars. In particular embodiments, the pressureregulation system may be configured to maintain a pressure within theMRS extruder at about 5 millibars, about 6 millibars, about 7 millibars,about 8 millibars, about 9 millibars, or about any suitable pressurebetween about 0 millibars and about 25 millibars.

In particular embodiments, the crystallizer causes the flakes to atleast partially reduce in size, which may, for example, reduce apotential for the flakes to stick together. In particular embodiments,the crystallizer may particularly reduce stickiness of larger flakes,which may, for example, include flakes comprising portions of the groundPET bottles which may be thicker than other portions of the PET bottles(e.g., flakes ground from a threaded portion of the PET bottle on whicha cap would typically be screwed).

Use of Curbside Recycling v. Deposit Bottles in Process

In various embodiments, the system is configured to utilize recycled PETof varying quality in the process described above. For example, invarious embodiments, the system is configured to produce bulkedcontinuous carpet filament from PET derived from PET bottles sourcedfrom curbside recycling sources (e.g., PET bottles that were collectedas part of a general bulk recycling program or other recycling source)as well as deposit PET bottles (e.g., bottles returned as part of adeposit program). In various embodiments, Curbside recycled bottles mayrequire more thorough processing in order to produce bulked continuousfilament, as curbside recycled PET bottles may be mixed in with andotherwise include contaminants such as, for example: other recyclablegoods (e.g., paper, other plastics, etc.), garbage, and other non-PETbottle items due to imperfect sorting of recycled goods or for any otherreason. Deposit PET bottles may include PET bottles with fewer unwantedcontaminants due in part because deposit PET bottles may be collectedseparately from other recyclable or disposable goods.

In various embodiments, curbside recycled PET bottles acquired duringparticular times of year may include more impurities and othercontaminants than at other times of the year. For example, curbsiderecycled PET bottles collected during summer months may comprise ahigher percentage of clear PET bottles (e.g., water bottles) at least inpart due to additional water consumption during summer months.

In various embodiments, the system described above may be configured toadjust particular components of the process based at least in part onthe source of recycled PET being used to produce the bulked continuouscarpet filament. For example, because deposit PET bottles include fewerimpurities that need to be removed during the initial cleaning andsorting phases of the process, the pressure regulation system may beconfigured to maintain a pressure within the MRS extruder that is higherthan a pressure that it would be configured to maintain for PET flakederived from curbside recycled PET bottles. In a particular embodiment,the pressure regulation system may be configured to maintain a pressurewithin the MRS extruder of between about 0 millibars and about 12millibars when flakes derived from deposit PET bottles are passingthrough the MRS extruder. In still other embodiments, the pressureregulation system may be configured to maintain a pressure within theMRS extruder of between about 5 millibars and about 10 millibars in suchinstances.

In various embodiments, the system is configured to determine a suitablepressure at which to maintain the pressure within the MRS extruder basedat least in part on the source of the recycled PET. In otherembodiments, the system is configured to omit one or more of the stepsabove or include one or more additional steps to the steps describedabove based at least in part on the source of the recycled PET.

The Use of Colored PET and Color Additives

In various embodiments, systems for manufacturing recycled bulkedcontinuous filament described above may utilize colored (non-clear)post-consumer PET bottles (e.g., or other containers) in addition to theclear PET bottles described elsewhere herein. For example, in particularembodiments, the system may utilize blue, green, amber or any othersuitable colored bottles in the production of recycled BCF (e.g., ratherthan removing substantially all of the colored PET from the recycled PETin the initial stages of the process). In certain embodiments, theprocess includes one or more additional steps that include, for example,adding one or more color additives (e.g., one or more solution dye colorconcentrates), which may, for example, dilute a discoloration of theresulting recycled fiber caused by using colored PET in the recyclingprocess.

Flake Color Ratios

In various embodiments, the PET bottles used in the production ofrecycled BCF may include particular percentages of clear and coloredbottles (e.g., by volume, by mass, etc.). For example, in particularembodiments, recycled BCF may be produced using at least about 80%(e.g., 80%) clear bottles and no more than about 20% (e.g., 20%) coloredbottles. In particular embodiments, the colored bottles that the systemuses along with clear bottles to produce the recycled BCF may includeonly recycled bottles of a particular color (e.g., only green bottles,only blue bottles, only amber bottles, etc.). In particular embodiments,the system may be configured to use bottles of a particular shade of aparticular color. For example, in various embodiments, the system may beconfigured to utilize lighter blue bottles (e.g., bottles of aparticular light shade of blue) but not to use darker blue bottles. Instill other embodiments, the system may be configured to use anysuitable colored bottles (e.g., or other sources of recycled PET) in anysuitable ratio.

In various embodiments, the process may utilize between about 6.5percent (e.g., 6.5 percent) and about nine percent (e.g., nine percent)colored PET with the remainder being clear PET. In other embodiments,the process may use between about six and about ten percent colored PET.In still other embodiments, the process may use up to about ten percentcolored PET with balance substantially clear PET. In still otherembodiments, the process may utilize between about one percent coloredPET and about ten percent colored PET with balance substantially clearPET. In other embodiments, the process may use any other suitable ratioof colored recycled PET to clear recycled PET.

Use of Colored Flake Based on Desired Carpet Color

In various embodiments, an amount of non-clear PET bottles used in theprocess may be based at least in part on a color of carpet into whichthe recycled BCF produced by the process will ultimately be made. Forexample, for darker carpets, the recycled BCF used in their creation maybe produced using a higher percentage of colored (e.g., non-clear) PETbottles. In various embodiments, the use of a higher percentage ofcolored PET bottles may result in darker recycled BCF filament, whichmay, for example, be unsuitable for the production of particular coloredcarpets (e.g., lighter carpets). Carpets which will ultimately be dyedin darker colors (e.g., or solution dyed into a darker color) may bemore suitable for production using recycled BCF produced at leastpartially from colored PET bottles. For example, the production ofrecycled BCF for use in brown carpets may utilize at least a particularamount of amber PET bottles in the recycling process (e.g., 20% amberand 80% clear, or any other suitable ratio).

In a particular example, the system may use 2% or less of non-clear PETbottles in the process when producing relatively light-colored BCF. Thismay help to reduce or eliminate the need to use offsetting colorconcentrate (as discussed in greater detail below) to achieve thedesired light-colored BCF.

In certain situations, it may be advantageous to use high percentages ofnon-clear PET bottles since doing so may reduce the amount of solutiondye needed to achieve the desired color. For example, it may beadvantageous to use over about 80%, over about 90%, over about 95%, orabout 100% non-clear PET in using the process to produce certaindark-colored (or other colored) recycled BCF. For example, in variousembodiments, it may be advantageous to use over 95% non-clear PET inproducing dark-green recycled BCF since doing so may reduce the amountof solution dye needed to attain the desired dark-green color.

In various embodiments, it may be acceptable to use the percentages ofnon-clear PET that are commonly available in purchased lots of curbsiderecycled bottles. Such percentages typically range from between about6.5% to 9.5% non-clear PET. In particular situations, where such rangesare acceptable, the system is adapted not to sort non-clear PET fromclear PET. Rather, non-clear and clear PET are processed and usedtogether. However, non-PET polymers may be separated from the mix anddiscarded as described above.

Use of Offsetting Color Concentrate with Colored PET

In particular embodiments, the system is configured to use any suitablesolution dyeing technique to at least partially offset (e.g.,substantially offset) any discoloration of the BCF filament resultingfrom the above process when utilizing colored recycled PET. In variousembodiments, the system is configured to add a color concentrate topolymer flakes prior to extrusion (e.g., or to polymer melt during orafter extrusion) in order to at least partially offset a coloration ofthe resultant filament due to the use of colored recycled PET. Inparticular embodiments, the color concentrate may include any suitablecolor concentrate, which may, for example, result in a particular colorof polymer fiber (e.g., bulked continuous filament) following extrusion.In various embodiments, adding color concentrate to the flakes prior toextrusion may result in polymer filament that is at least partiallyimpregnated (e.g., impregnated) with a color pigment. In variousembodiments, the impregnated color pigment may offset any discolorationof the resulting fiber that may have resulted due to the use of coloredrecycled PET in the extrusion process. In particular embodiments, carpetproduced from solution dyed filament may be highly resistant to colorloss through fading from sunlight, ozone, harsh cleaning agents such asbleach, or other factors.

In various embodiments, the color concentrate includes any suitabledispersion of color in a compatible carrier. In some embodiments, colorconcentrates are designed so that, when added to a natural resin (e.g.,PET) in a set proportion, they color the resin substantially evenly(e.g., evenly) to match a desired color. In some embodiments, the colormay comprise mixtures of pigments, which may, for example, includeparticles of insoluble colored material, in the resin. In otherembodiments, color concentrates may include one or more polymer-solubledyes that are suitable alone or in combination with one or morepigments.

In particular embodiments, the system is configured to add between abouttwo percent (e.g., two percent) and about three percent (e.g., threepercent) color concentrate by mass to the polymer flake. In otherembodiments, the system is configured to add between about zero percent(e.g., zero percent) and about three percent (e.g., three percent) colorconcentrate by mass or volume. In still other embodiments, the system isconfigured to add up to about six percent (e.g., six percent) colorconcentrate by mass to the polymer flake prior to extrusion. In someembodiments, the system is configured to add between about one percent(e.g., one percent) and about three percent (e.g., three percent) colorconcentrate by mass to the polymer flake. In still other embodiments,the system is configured to add any suitable ratio of color concentrateto polymer flake in order to achieve a particular color of moltenpolymer (and ultimately polymer fiber) following extrusion.

FIG. 4 depicts an embodiment in which color concentrate is added to thepolymer flake (e.g., mix of colored and clear PET flake) prior tofeeding the flake through the first single-screw extruder section 410.It should be understood that, in other embodiments, the colorconcentrate may be added during any other suitable phase of the processdescribed in this document. For example, in various embodiments, such asany of the examples discussed above, the system may be configured to addthe color concentrate following extrusion of the polymer flake by thefirst single-screw extruder section 410 but prior to feeding theresultant polymer melt through the extruder's MRS section 420 discussedherein. In still other embodiments, the system may add the colorconcentrate after the flake has passed through the MRS extruder's MRSsection 420 prior to passing the polymer melt through the second singlescrew section 440 discussed herein. In still other embodiments, thesystem may add the color concentrate while the flakes and/or polymermelt are being extruded in the first single-screw extruder section 410,MRS Section 420, second single screw section 440, or at any othersuitable phase of the process. In still other embodiments, the systemmay add the color concentrate during one or more (e.g., a plurality) ofthe phases of the process described herein (e.g., the system may addsome color concentrate to the polymer flake prior to passing the flakethrough the single-screw extruder section 410 and some additionalsolution color concentrate following extrusion through the MRS Section420).

In various embodiments, the use of a color concentrate at leastpartially masks any coloration of the resulting in a bulked continuousfilament created using the above process using colored recycled PET. Insuch embodiments, the resulting bulked continuous filament may have acolor that is substantially similar to a color of bulked continuousfilament produced using substantially only substantially clear (e.g.,clear) recycled PET and a color concentrate.

Substantially Automated Solution Dyeing

In various embodiments, the system is configured to substantiallyautomatically adjust an amount of color concentrate added to the polymerflake and/or polymer melt in order to produce a desired color of BCFfilament. In various other embodiments, the system is configured tosubstantially automatically determine an amount of color concentrate toadd to the colored PET to sufficiently offset the color of the coloredPET. In such embodiments, the system may, for example, use a suitablefeedback loop that includes: (1) determining a color of bulkedcontinuous filament produced by the process; (2) determining whether thecolor is acceptable (e.g., the color is determined to be a particulartarget color and/or the color is determined to meet one or morepre-determined color guidelines); and (3) substantially automaticallyadjusting an amount of color concentrate being added to the colored PETupstream based at least in part on the determined color (whether thedetermined color is acceptable according to one or more pre-determinedcolor guidelines). In particular embodiments, the system is adapted toautomatically adjust an amount of color concentrate being added to thecolored (non-clear) PET to assure that it is sufficient for theresulting colored PET to satisfy the one or more pre-determined colorguidelines.

Non-Solution Dyeing to Mask Colored PET in Resultant Filament

In various embodiments, the process may utilize any suitable dyeingtechnique other than the solution dyeing technique described above to atleast partially mask a coloration of the filament produced using therecycled BCF process described herein with colored recycled PET. Forexample, in various embodiments, the process may utilize any suitableskein dyeing technique, any suitable continuous dyeing technique, anysuitable space dyeing technique, any suitable beck dyeing technique, orany other suitable dyeing technique or suitable combination of dyeingtechniques.

Mixing of PTT with PET to Increase Dyeability

In various embodiments, such as embodiments in which the processincludes adding one or more solution dyes to recycled PET that includescolored PET, the process may include adding polytrimethyleneterephthalate (PTT) (or any other suitable additive) to the PET prior toextrusion, during extrusion, along with the color concentrate,separately from the color concentrate, or at any other suitable time. Invarious embodiments, the mixture of PTT (or other additive) and PET mayhave an enhanced dyeability compared to PET that has not been mixed withPTT. In particular embodiments, the process includes using a mixture ofbetween about five percent (e.g., five percent) and about fourteenpercent (e.g., fourteen percent) PTT (or other additive) in the mixtureby mass or volume. In other embodiments, the process includes using amixture of between about six percent (e.g., six percent) and about tenpercent (e.g., ten percent) PTT (or other additive) in the mixture bymass or volume. In still other embodiments, the process includes addingup to about fourteen percent (e.g., fourteen percent) PTT (or otheradditive) by volume or mass (e.g., between about zero percent and aboutfourteen percent PTT). In various embodiments, the addition of PTT (orother additive) to the PET may reduce a cost of dyeing the resultingfiber.

In various embodiments, the process may utilize virgin PTT. In stillother embodiments, the process may utilize recycled PTT. In someembodiments, PTT may be recycled from any suitable source such as, forexample, recycled PTT carpet, recycled food containers, and/or othersuitable PTT products. In various embodiments, the PTT may includerecycled PTT recovered (e.g., recycled) using the process describedherein.

In various embodiments, the above process may be suitable for recyclingPTT for use in mixing the recycled PTT (or other suitable additive) withPET to improve dyeability of the PET due to the similar chemicalcomposition of PTT and PET. The resulting combination may have a higherdurability and resilience than conventional polyesters (e.g., PET). Inparticular embodiments, PTT is particularly useful in the production ofcarpet due to PTT's stain-resistant qualities. PTT carpets may, forexample, at least generally maintain their original appearance throughsimple vacuuming and hot water extraction. This may, for example, resultin a longer lifespan of carpet produced with PTT. In particularembodiments, PTT is substantially hydrophobic, which may contribute toPTT carpet's stain resistance. In various embodiments, PTT carpeting isalso substantially soft (e.g., to the touch). PTT carpet's softness mayresult from, for example, a lack of topically-applied chemicals forstain protection due to PTT's inherent hydrophobic tendencies. It shouldbe understood, based on the above discussion, that any suitable additivemay be used in place of, or in addition to, PTT in the examplesdiscussed above.

Addition of Dye Enhancers

In various embodiments, such as embodiments in which the processincludes adding one or more dye enhancers to recycled PET that includesnon-clear PET, the process may include adding DEG (or any other suitabledye enhancer) to the PET prior to extrusion, during extrusion, alongwith color concentrate, separately from color concentrate, or at anyother suitable time. In various embodiments, the mixture of the dyeenhancer and PET may have an enhanced dyeability compared to PET thathas not been mixed with the dye enhancer. In particular embodiments, theprocess includes using a mixture of between about zero percent (e.g.,zero percent) and about five percent (e.g., five percent) dye enhancer(e.g., DEG) in the mixture by mass or volume. In certain embodiments,the process includes using a mixture of between about one percent (e.g.,one percent) and about two percent (e.g., two percent) dye enhancer(e.g., DEG) in the mixture by mass or volume.

CONCLUSION

Many modifications and other embodiments of the invention will come tomind to one skilled in the art to which this invention pertains havingthe benefit of the teachings presented in the foregoing descriptions andthe associated drawings. For example, although the vacuum systemdiscussed above is described as being configured to maintain thepressure in the open chambers of the MRS extruder to about 1 mbar, inother embodiments, the vacuum system may be adapted to maintain thepressure in the open chambers of the MRS extruder at pressures greaterthan, or less than, 1 mbar. For example, the vacuum system may beadapted to maintain this pressure at between about 0.5 mbar and about 12mbar.

Similarly, although various embodiments of the systems described abovemay be adapted to produce carpet filament from substantially onlyrecycled PET (so the resulting carpet filament would comprise, consistof, and/or consist essentially of recycled PET), in other embodiments,the system may be adapted to produce carpet filament from a combinationof recycled PET and virgin PET. The resulting carpet filament may, forexample, comprise, consist of, and/or consist essentially of betweenabout 80% and about 100% recycled PET, and between about 0% and about20% virgin PET.

Furthermore, it should be understood that when ratios of polymers arediscussed herein (e.g., as a percentage) such as a ratio of coloredrecycled PET to clear recycled PET, color concentrate to polymer flake,etc., the percentages may include a percentage by volume, a percentageby mass, a percentage by weight, or any other suitable relative measure.

Also, while various embodiments are discussed above in regard toproducing carpet filament from PET, similar techniques may be used toproduce carpet filament from other polymers. Similarly, while variousembodiments are discussed above in regard to producing carpet filamentfrom PET, similar techniques may be used to produce other products fromPET or other polymers.

In addition, it should be understood that various embodiments may omitany of the steps described above or add additional steps.

In light of the above, it is to be understood that the invention is notto be limited to the specific embodiments disclosed and thatmodifications and other embodiments are intended to be included withinthe scope of the appended claims. Although specific terms are employedherein, they are used in a generic and descriptive sense only and notfor the purposes of limitation.

What is claimed is:
 1. A method of manufacturing bulked continuouscarpet filament, the method comprising: (A) providing an extrusionsystem that comprises: (i) a first extruder; (ii) a second extruder; and(iii) a pressure regulation system that is adapted to maintain apressure within the first and second extruders between about 0 millibarsand about 5 millibars; (B) using the pressure regulation system toreduce a pressure within the first and second extruders to between about0 millibars and about 5 millibars; (C) providing a plurality of polymerflakes, the plurality of polymer flakes comprising between about sixpercent and about ten percent colored recycled polyethyleneterephthalate (PET) flakes and balance substantially clear recycled PETflakes; (D) providing one or more color additives; (E) adding the one ormore color additives to the plurality of polymer flakes such that theresulting mixture comprises between about zero percent and about threepercent of the one or more color additives by weight; (F) whilemaintaining the pressure within the first and second extruders betweenabout 0 millibars and about 5 millibars, passing the plurality ofpolymer flakes and the one or more color additives through the extrusionsystem to form a polymer melt so that: (1) a first portion of thepolymer melt passes through the first extruder, and (2) a second portionof the polymer melt passes through the second extruder; and (G) afterthe step of passing the polymer melt through the extrusion system,forming the recycled polymer into bulked continuous carpet filament. 2.The method of claim 1, wherein the colored recycled PET flakes consistessentially of colored PET flakes derived from recycled PET bottles. 3.The method of claim 2, wherein the colored recycled PET flakes compriseone or more types of PET flake selected from a group consisting of: i.amber PET flake; ii. blue PET flake; and iii. green PET flake.
 4. Themethod of claim 1, further comprising: providing a color sensorconfigured to determine a color of the polymer melt; and substantiallyautomatically adjusting an amount of the one or more color additivesadded to the plurality of polymer flakes based at least in part on thedetermined color of the polymer melt.
 5. The method of claim 4, whereinthe plurality of polymer flakes comprises: between about six percent andabout ten percent colored recycled PET flakes by weight; up to about sixpercent polytrimethylene terephthalate (PTT) by weight; and balancesubstantially clear recycled PET flakes.
 6. The method of claim 5,wherein the plurality of polymer flakes comprises: between about sevenpercent and about nine percent colored recycled PET flakes by weight;between about five percent and about six percent PTT by weight; andbalance substantially clear recycled PET flakes.
 7. The method of claim1, wherein the one or more color additives at least partially offset acoloration of the bulked continuous carpet filament from the coloredrecycled PET flakes.
 8. The method of claim 1, wherein the one or morecolor additives comprise a solution dye concentrate.
 9. The method ofclaim 1, wherein the extrusion system is one of a twin screw extruder, amultiple screw extruder, or a planetary extruder.
 10. A method ofmanufacturing carpet filament from clear and colored recycled PETbottles comprising the steps of: (A) providing a plurality of recycledPET bottles; (B) grinding the plurality of recycled PET bottles into agroup of polymer flakes, the group of polymer flakes comprising up toabout ten percent colored polymer flakes and balance substantially clearpolymer flakes; (C) washing the group of polymer flakes; (D) providing acolor additive; (E) mixing the color additive with the group of polymerflakes to form a color additive-polymer mixture comprising up to aboutthree percent color additive by weight; (F) melting the coloradditive-polymer mixture to produce a polymer melt; (G) providing anextruder that extrudes material in a plurality of different extrusionstreams; (H) reducing a pressure within the extruder to between about 0millibars and about 12 millibars; (I) while maintaining the pressurewithin the extruder between about 0 millibars and about 12 millibars,passing the polymer melt through the extruder so that the polymer meltis divided into a plurality of extrusion streams, each having a pressurebetween about 0 millibars and about 12 millibars; (J) after passing thepolymer melt through the extruder, filtering the polymer melt through atleast one filter; and (K) after passing the polymer melt through thefilter, forming the polymer melt into bulked continuous carpet filament.11. The method of claim 10, the method further comprising: providingpolytrimethylene terephthalate (PTT); and adding the PTT to the coloradditive-polymer mixture, such that the color additive-polymer mixturecomprises: up to about three percent color additive by weight; up toabout six percent PTT by weight; and balance the group of polymerflakes.
 12. The method of claim 11, wherein adding the PTT to the coloradditive-polymer mixture increases the dyeability of the resultant coloradditive-polymer mixture.
 13. The method of claim 12, the method furthercomprising adding the PTT to the color additive-polymer mixture, suchthat the color additive-polymer mixture comprises: between about twopercent and about three percent color additive by weight; between aboutfive percent and about six percent PTT by weight; and balance the groupof polymer flakes.
 14. The method of claim 10, the method furthercomprising: providing one or more color sensors configured to determinea color of the polymer melt; and substantially automatically adjustingan amount of the color additive added to the color additive-polymermixture based at least in part on the determined color of the polymermelt.
 15. The method of claim 14, wherein the one or more color sensorscomprise one or more color sensors selected from a group consisting of:one or more cameras; and one or more spectrographs.
 16. The method ofclaim 10, wherein the color additive at least partially masks acoloration of the bulked continuous carpet filament caused by thecolored polymer flakes.
 17. A method of manufacturing bulked continuouscarpet filament, the method comprising: (A) providing an extrusionsystem that comprises: (i) a first extruder; (ii) a second extruder;(iii) a third extruder; (iv) a fourth extruder; and (v) a pressureregulation system that is adapted to maintain a pressure within thefirst, second, third, and fourth extruders between about 1 millibar andabout 18 millibars; (B) using the pressure regulation system to reduce apressure within the first, second, third, and fourth extruders tobetween about 0 millibars and about 18 millibars; (C) while maintainingthe pressure within the first, second, third, and fourth extrudersbetween about 1 millibar and about 18 millibars, passing a polymer meltthrough the extrusion system so that: (1) a first portion of the meltpasses through the first extruder, (2) a second portion of the meltpasses through the second extruder, (3) a third portion of the meltpasses through the third extruder, and (4) a fourth portion of the meltpasses through the fourth extruder, wherein: the polymer melt comprises:between about seven percent and about nine percent colored recycled PETby weight; between about two percent and about three percent coloradditive by weight; and balance recycled substantially clear PET; and(D) after the step of passing the polymer melt through the extrusionsystem, forming the polymer melt into bulked continuous carpet filament.18. The method of claim 17, further comprising: providing one or morecolor sensors configured for determining a color of the polymer melt;using the one or more color sensors to determine the color of thepolymer melt; determining whether the color is a desired color; at leastpartially in response to determining that the color is not a desiredcolor, taking an action selected from a group consisting of: increasingan amount of color additive in said polymer melt; and decreasing anamount of color additive in said polymer melt.
 19. The method of claim17, wherein the polymer melt comprises: between about seven percent andabout nine percent colored recycled PET by weight; up to about fivepercent PTT by weight; between about two percent and about three percentcolor additive by weight; and balance recycled substantially clear PET.20. The method of claim 17, wherein the color additive at leastpartially masks a coloration of the bulked continuous carpet filamentcaused by the colored recycled PET.
 21. The method of claim 20, whereinthe bulked continuous carpet filament has a color that is substantiallythe same as a color of bulked continuous carpet filament producedsubstantially only from recycled substantially clear PET.
 22. The methodof claim 17, wherein the colored recycled PET is derived essentiallyfrom recycled PET bottles having a color selected from a groupconsisting of: i. amber; ii. blue; and iii. green.